I have data in a BigQuery table that looks like this:
[
{ "id": 1, "labels": [{"key": "a", "value": 1}, {"key": "b", "value": 2}] },
{ "id": 2, "labels": [{"key": "a", "value": 1}, {"key": "b", "value": 3}] },
// a lot more rows
]
My question is, how can I find all rows where "key" = "a", "value" = 1, but also "key" = "b" and "value" = 3?
I've tried various forms of using UNNEST but I haven't been able to get it right. The CROSS JOIN leaves me with one row for every object in the labels array, leaving me unable to query by both of them.
Try this:
select *
from mytable
where exists (select 1 from unnest(labels) where key = "a" and value=1)
and exists (select 1 from unnest(labels) where key = "b" and value=3)
Assuming there is no duplicate entries in labels array - you can use below
select *
from `project.dataset.table` t
where 2 = (
select count(1)
from t.labels kv
where kv in (('a', 1), ('b', 3))
)
You can try parse JSON and then you can apply different filter conditions on it as per your requirements, in following query I have tried to identified which all records have Key=a then I tried to identify which record has value=30 then joined them through id :-
WITH data1 AS (
SELECT '{ "id": 1, "labels": [{"key": "a", "value": 11}, {"key": "b", "value": 22}] }' as c1
union all
SELECT '{ "id": 2, "labels": [{"key": "a", "value": 10}, {"key": "b", "value": 30}] }' AS C1
)
select T1.id, T1.C1, T1.key, T2.value from
(SELECT JSON_EXTRACT_SCALAR(c1 , "$.id") AS id,
json_extract_scalar(curSection, '$.value') as value, json_extract_scalar(curSection, '$.key') as key,
c1
FROM data1 tbl LEFT JOIN unnest(json_extract_array(tbl.c1, '$.labels')
) curSection
where json_extract_scalar(curSection, '$.key')='a') T1,
(
SELECT JSON_EXTRACT_SCALAR(c1 , "$.id") AS id,
json_extract_scalar(curSection, '$.value') as value, json_extract_scalar(curSection, '$.key') as key,
c1
FROM data1 tbl LEFT JOIN unnest(json_extract_array(tbl.c1, '$.labels')
) curSection
where json_extract_scalar(curSection, '$.value')='30') T2
where T1.id = T2.id
Hopefully it may work for you.
Related
We have the following table
WITH fake_data(columnA, columnB, columnC) as (
select * from values
(1, 'hello1', 'world18'),
(1, 'hello2', 'world27'),
(2, 'hello9', 'world36')
(3, NULL, 'world35')
(10, 'hello13', 'world5')
)
We convert the entire table into a single column that has a JSON-like structure
CREATE OR REPLACE TEMPORARY TABLE LISTE_JSON (V variant)
AS
WITH COLONNE_KEY
AS (
SELECT
ROW_NUMBER () OVER (ORDER BY columnA DESC) KEY_AUTO
,A.*
FROM fake_data A
),
COLONNE_OBJECT
AS (
SELECT
object_agg(
TO_CHAR(KEY_AUTO ) ,
object_construct(
'columnA', IFNULL(columnA,''),
'columnB', IFNULL(columnB,''),
'columnC', IFNULL(columnC,''),
)
)AS COLONNE_OBJECT
FROM COLONNE_KEY
)
SELECT *
FROM COLONNE_OBJECT;
So far everything is going well.
Now how do I read the variant column through a SELECT and see it as a table, as it was at the beginning?
Ex:
SELECT *
FROM LISTE_JSON
COLUMNA COLUMNB COLUMNC
1 hello1 world18
1 hello2 world27
2 hello9 world36
3 '' world35
10 hello13 world5
You can ether use PIVOT to pull with parts, or you can hand roll the pivot via GROUP BY
SELECT
columna
,max(iff(columnb='hello1', columnc, null)) as hello1
,max(iff(columnb='hello2', columnc, null)) as hello2
,max(iff(columnb='hello3', columnc, null)) as hello3
from table
group by 1 order by 1;
So lets start with working "example code"
WITH fake_data(columnA, columnB, columnC) as (
select * from values
(1, 'hello1', 'world18'),
(1, 'hello2', 'world27'),
(2, 'hello9', 'world36'),
(3, NULL, 'world35'),
(10, 'hello13', 'world5')
), COLONNE_KEY AS (
SELECT
ROW_NUMBER () OVER (ORDER BY columnA DESC) KEY_AUTO
,A.*
FROM fake_data A
), COLONNE_OBJECT AS (
SELECT
object_agg( KEY_AUTO::text ,
object_construct('columnA', IFNULL(columnA::text,''),
'columnB', IFNULL(columnB::text,''),
'columnC', IFNULL(columnC::text,'')
)
)AS COLONNE_OBJECT
FROM COLONNE_KEY
)
SELECT *
FROM COLONNE_OBJECT;
gives:
COLONNE_OBJECT
{ "1": { "columnA": "10", "columnB": "hello13", "columnC": "world5" }, "2": { "columnA": "3", "columnB": "", "columnC": "world35" }, "3": { "columnA": "2", "columnB": "hello9", "columnC": "world36" }, "4": { "columnA": "1", "columnB": "hello1", "columnC": "world18" }, "5": { "columnA": "1", "columnB": "hello2", "columnC": "world27" } }
which you would like to get back into it original table form
thus
SELECT
f.value:"columnA"::number as columna,
f.value:"columnB"::text as columnb,
f.value:"columnC"::text as columnc
FROM COLONNE_OBJECT, table(flatten(input=>colonne_object)) f;
gives you back
COLUMNA
COLUMNB
COLUMNC
10
hello13
world5
3
<empty string>
world35
2
hello9
world36
1
hello1
world18
1
hello2
world27
and the empty string can be swapped back in via
nullif(f.value:"columnB"::text,'') as columnb,
I have this table
id name json
1 alex {"type": "user", "items": [ {"name": "banana", "color": "yellow"}, {"name": "apple", "color": "red"} ] }
2 peter {"type": "user", "items": [ {"name": "watermelon", "color": "green"}, {"name": "pepper", "color": "red"} ] }
3 john {"type": "user", "items": [ {"name": "tomato", "color": "red"} ] }
4 carl {"type": "user", "items": [ {"name": "orange", "color": "orange"}, {"name": "nut", "color": "brown"} ] }
Important, each json object can have different number of "items", but what I need is the "product name" of JUST the object that matched in the WHERE condition.
My desired output would be the two first columns and just the name of the item, WHERE the color is like %red%:
id name fruit
1 alex apple
2 peter pepper
3 john tomato
select id, name, ***** (this is what I don't know) FROM table
where JSON_EXTRACT(json, "$.items[*].color") like '%red%'
I would recommend json_table(), if you are running MySQL 8.0:
select t.id, t.name, x.name as fruit
from mytable t
cross join json_table(
t.js,
'$.items[*]' columns (name varchar(50) path '$.name', color varchar(50) path '$.color')
) x
where x.color = 'red'
This function is not implemented in MariaDB. We can unnest manually with the help of a numbers table:
select t.id, t.name,
json_unquote(json_extract(t.js, concat('$.items[', x.num, '].name'))) as fruit
from mytable t
inner join (select 0 as num union all select 1 union all select 2 ...) x(num)
on x.num < json_length(t.js, '$.items')
where json_unquote(json_extract(t.js, concat('$.items[', x.num, '].color'))) = 'red'
You can use JSON_EXTRACT() function along with Recursive Common Table Expression in order to generate rows dynamically such as
WITH RECURSIVE cte AS
(
SELECT 1 AS n
UNION ALL
SELECT n + 1
FROM cte
WHERE cte.n < (SELECT MAX(JSON_LENGTH(json)) FROM t )
)
SELECT id, name,
JSON_UNQUOTE(JSON_EXTRACT(json,CONCAT('$.items[',n-1,'].name'))) AS fruit
FROM cte
JOIN t
WHERE JSON_EXTRACT(json,CONCAT('$.items[',n-1,'].color')) = "red"
Demo
I have a table main like this:
create foreign table main (
"id" character varying not null,
"a" character varying not null,
"b" character varying not null
)
And I have another table, not_main, like this:
create foreign table not_main (
"id" character varying not null,
"fk" character varying not null,
"d" character varying not null,
"e" character varying not null
)
Should I want a query whose return is like:
json
0 {"id": "id_main_0", "a": "a0", "b": "b0", "cs": [{"id": "id_not_main_0", "fk": "id_main_0", "d": "d0", "e": "e0"}, {"id": "id_not_main_1", "fk": "id_main_0", "d": "d1", "e": "e1"}]}
1 {"id": "id_main_1", "a": "a1", "b": "b1", "cs": [{"id": "id_not_main_2", "fk": "id_main_1", "d": "d2", "e": "e3"}, {"id": "id_not_main_3", "fk": "id_main_1", "d": "d3", "e": "e3"}]}
How should I do it?
I tried:
select
json_build_object(
'id', m."id",
'a', m."a",
'b', m."b",
'cs', json_build_array(
json_build_object(
'd', nm."d",
'e', nm."e"
)
)
)
from main m
left join not_main nm on
nm."requisitionId" = m.id;
But it returns only one element in cs:
json
0 {"id": "id_main_0", "a": "a0", "b": "b0", "cs": [{"id": "id_not_main_0", "fk": "id_main_0", "d": "d0", "e": "e0"}]}
1 {"id": "id_main_1", "a": "a1", "b": "b1", "cs": [{"id": "id_not_main_2", "fk": "id_main_1", "d": "d2", "e": "e3"}]}
OBS: consider that the constraints of and between main and not_main are properly modeled, e.g., that I actually have both id columns as PKs and that fk is references the id column of main.
You want json array aggregation. Basically, you just need to change json_build_array() to json_agg(), and to add a group by clause:
select
json_build_object(
'id', m.id,
'a', m.a,
'b', m.b,
'cs', json_agg(
json_build_object(
'd', nm.d,
'e', nm.e
)
)
)
from main m
left join not_main nm on
nm.requisitionId = m.id
group by m.id, m.a, m.b
I could really use some help here before my mind explodes...
Given the following data structure:
SELECT * FROM (VALUES (1, 1, 1, 1), (2, 2, 2, 2)) AS t(day, apple, banana, orange);
day | apple | banana | orange
-----+-------+--------+--------
1 | 1 | 1 | 1
2 | 2 | 2 | 2
I want to construct a JSON object which looks like the following:
{
"data": [
{
"day": 1,
"fruits": [
{
"key": "apple",
"value": 1
},
{
"key": "banana",
"value": 1
},
{
"key": "orange",
"value": 1
}
]
}
]
}
Maybe I am not so far away from my goal:
SELECT json_build_object(
'data', json_agg(
json_build_object(
'day', t.day,
'fruits', t)
)
) FROM (VALUES (1, 1, 1, 1), (2, 2, 2, 2)) AS t(day, apple, banana, orange);
Results in:
{
"data": [
{
"day": 1,
"fruits": {
"day": 1,
"apple": 1,
"banana": 1,
"orange": 1
}
}
]
}
I know that there is json_each which may do the trick. But I am struggling to apply it to the query.
Edit:
This is my updated query which, I guess, is pretty close. I have dropped the thought to solve it with json_each. Now I only have to return an array of fruits instead appending to the fruits object:
SELECT json_build_object(
'data', json_agg(
json_build_object(
'day', t.day,
'fruits', json_build_object(
'key', 'apple',
'value', t.apple,
'key', 'banana',
'value', t.banana,
'key', 'orange',
'value', t.orange
)
)
)
) FROM (VALUES (1, 1, 1, 1), (2, 2, 2, 2)) AS t(day, apple, banana, orange);
Would I need to add a subquery to prevent a nested aggregate function?
Use the function jsonb_each() to get pairs (key, value), so you do not have to know the number of columns and their names to get a proper output:
select jsonb_build_object('data', jsonb_agg(to_jsonb(s) order by day))
from (
select day, jsonb_agg(jsonb_build_object('key', key, 'value', value)) as fruits
from (
values (1, 1, 1, 1), (2, 2, 2, 2)
) as t(day, apple, banana, orange),
jsonb_each(to_jsonb(t)- 'day')
group by 1
) s;
The above query gives this object:
{
"data": [
{
"day": 1,
"fruits": [
{
"key": "apple",
"value": 1
},
{
"key": "banana",
"value": 1
},
{
"key": "orange",
"value": 1
}
]
},
{
"day": 2,
"fruits": [
{
"key": "apple",
"value": 2
},
{
"key": "banana",
"value": 2
},
{
"key": "orange",
"value": 2
}
]
}
]
}
Right now, I have an an array that I'm able to select off a table.
[{"_id": 1, "count: 3},{"_id": 2, "count: 14},{"_id": 3, "count: 5}]
From this, I only need the count for a particular _id. For example, I need the count for
_id: 3
I've read the documentation but I haven't been able to figure out the correct way to get the object.
WITH test_array(data) AS ( VALUES
('[
{"_id": 1, "count": 3},
{"_id": 2, "count": 14},
{"_id": 3, "count": 5}
]'::JSONB)
)
SELECT val->>'count' AS result
FROM
test_array ta,
jsonb_array_elements(ta.data) val
WHERE val #> '{"_id":3}'::JSONB;
Result:
result
--------
5
(1 row)